Refrigerant control



Aug. 11, 1936. T. E. DRUMMOND REFRIGERANT CONTROL Filed Feb. 26, 1934 INVENTOR. THorvms E. DRU MOND n y ATTORNEY Patented Aug. 11, 19361' P Tiziu'r OFFICE the refrigerant expansion in a refrigerating systern and'relates' more. particularly to the autoant line at the high pressure side of the com-x a pressor and provide a drop in pressure there v Devices of this character most generally commatic thermostatic control of said means and prise avariable throttling valve in the refrigerthrough sufficient to cause vaporizing of the liquid refrigerant and serve between limits of opening thereof to control the heat transfer of the system. This latter function of the valve is utilized to maintain the temperature of the refrigerating room-between desirable limits by the combining with the valve of a thermostatic means for controlling the valve opening in accordance with the temperature of the refrigerating room, the relation as between the degree of valve opening and temperature as may be understood being an inverse one. The thermostatic means here mentioned usually include a tube having sealed therein, and against a moving valve opening part of the valve, 9. gas such as ethyl chloride which is responsive to changes in temperature by proportional changes in pressure. Heretofore it has i been the custom to mount the thermo-control tube directly in the refrigerant .line or in direct thermal contact with the cooling pipe defining the line to control theope'ning ofithe expansion valve in accordance with the temperature of the refrigerant which may be expected to reflectthe temperature of the refrigerating room. Disadvantages attending this method of attachment of the thermo-controi tube, however, arise'by reason of abrupt changes and inconsistencies in the refrigerant itself. For example in the flow of refrigerant through the cooling pipes there is likely to be presentsmall pockets of warm refrigerant liquid followed perhaps by an extremely cold pocket of gas which on successive contact with the tube causes first an abrupt opening of the expansion valve which may flood the suc carry a pocket of liquid or warm gas into en ement with the tube, the motor and compressor which had just stopped operation will be instantly started and momentarily kept in operation pending the passage of the warm fluid pocket past the tube. In-instances following considerable opening and closing of doors leading to the refrigerating rooms, the motor and compressor afford, in the case of emergency, such as the Assumes. February. 26, 1934. Serial No. 112,31 1 a (crass-92) ,iilhe-invention relatesto means for controlling ual starting and stopping of themotor and )generator, as will be understood, not only wastefully' 5 consumes a. substantial amount of power but also is a principal factor inducing wear of the apparatus. In accordance with my invention, however, and as a principal obiect'thereof, I-arrange for the mounting of the thermo-control tube in 10 a the air of the refrigerating room so as to be directly responsive to the temperature of the room rather than that 'of the refrigerant. In this way the circulating r'nixing, effect of the heat of the room I air itself establishes a mean 15. temperature about the control tube and, as will be understood, this mean temperature, by rea---' son of the time elementincurred in the evening out of the air of differentheats, tends to lag behind either a rising or decreasing temperature in the room. Thus the fluid response in the control tube will never be motivated by either the extreme high or low temperatures to which at least certain parts of the room are subjected and as a result the variation in-opening of the ex* pansion valve is reduced to a minimum and the maintenance of the room temperature to an almost unvarying average is insured. Correspondingly, as will be clear, there will be a minimum starting and stopping of the motor and compressor and a resultant decrease in waste and wear hereinbefore mentioned and in addition the balance of heat transfer between the air in the refrigerating room and the cooling pipes will be maintained in a steady slowly heating or cooling, 35 substantially equilibrium state.

Another object of the invention is to provide an expansion valve and associated-thermo-control tube of the character described whichwill 4 breaking of the control tube, for the rendering 0 of the valve operation automatically r nsive to and exclusively controlled by thecgt ssure in the cooling pipes, whereby during su ,periods of use awaiting repair or replacement of the tube, an automatically controlled valve of a type well knownin the art may be provided.

A further 'object of the invention is to provide means in a valve of the character described for maintaining the valve parts sumciently warm toprevent freezing and sticking of moisture therein whereby the smoothness and .nicety of the automatically operating features will at all times be insured. h

Still another object of the invention is to proing a valve plug vide a refrigerant control of the character described which will individually control each of a plurality of parallel refrigerating units supplied from a central compressor without permitting the establishment of pressure differentials between the units and the resultant interchange of refrigerant therebetween, whereby. each of said units may be maintained at a substantially constant low temperature irrespective of the temperature or use of the other units.

The invention possesses other objects and features of advantage, some of which, with the foregoing, will be set forth in the following description of the preferred form of the invention which is illustrated in the drawing accompanying and forming partof the specification. It is to be understood, however, that variations in the showing made by the said drawing and description may be adopted within the scope of the invention as setforth in the claims. Referring to said drawing:

Figure 1 is a vertical sectional view of the refrigerant expansion valve of my invention.

Figure 2 is avertical sectional view of the back pressure checkvalve of my invention.

Figure 3 is a diagrammatic. layout of the refrigerant control and fluid system as applied to a plurality of units.

Referring more particularly to the drawing, the expansion valve 6 of my invention is arranged for insertion in a'refrigerant line 1 at the high pressure side of a compressor 8 just ahead of the cooling tubes 9 in a refrigerating chamber II. The valve proper comprises an outer casing l2 defining an inner valve chamber l3 and is provided with inlet and discharge nipples l4 and 16 for connection in the refrigerant line 1. As here shown, the inlet nipple II is extended centrally'into the chamber I3 and is provided adjacent the inner end thereofwith a side opening J! 'forcommunication with the chamber. Surrounding the nipple l4 and carryl8 formovement to and from a seated position in the opening I! is a yoke member l9. Means for urging the yoke to position closing the valve here include a helical spring 2| which engages between the yoke and a plate member 22 positioned at the top of the chamber l3. The member 22 is preferably arranged for arfiustment of the spring tension and for this purpose is provided with a stem portion 23 which is threadably engaged with and extended through atop cap member 24 for ready adjustment at the outer side of the casing. In order that the amount, of total valve opening may be adjusted independent -of the spring tension, the

valve plug I8 is preferably threadably carried in the yoke for adjustment to and from the valve opening. Tofacilitate this latter adjustment a rod 27 is fixed to the upper side of the valve plug and extended centrally through the spring 2| and a bore 28 in the stem 23 and is provided at its outer end with a'suitable knob 29 for engagement at the outer side of the stem. Preferably the engagement of the rod andbore is such as to provide both relative rotationand longitudinal movement of. the

control tube flarranged with one end 33 thereof extended in and having thermal contact with the air in the refrigerating room and having the other end thereof connected to the lower end of the valve casing for applying the pres- 5 sure of the expanded or contracted contents 3 thereof againsta flexible diaphragm 34 which is extended across the valve casing in a man'- ner defining an individual expandible pressure chamber 36 at the bottom of the casing chamber l3. Mounted on'the diaphragm for reciprocal movement therewith is a stem 31 which engages at its upper end with the .bottom of the ,yoke member IQ for urging thelatter to valve opening position or permitting retraction thereof under the action of the spring 2| in, accordance with the pressure in the chamber 36. Tofacilitate assembly of the parts and to provide for an adjustable spacing of the diaphragm and yoke, the stem may be formed of two removable sections 38 and 39 with the latter, as here shown threadably engaged in' the yoke for longitudinal adjustment. In order that a pressure differential may be established between the opposite sides of the diaphragm 25 for movement thereof proportional to the pressure in the chamber 36, the valve casing is preferably opened to atmosphere, as at 4|, above the upper surface of the diaphragm so as to afford expansion of the latter against a sub- 30 stantially constant atmospheric pressure. Thus it will now be clear the warming of the air in the refrigerating room will be accompanied "by an expansion of the fluid in the thermo-control ,tube and an opening of the expansion whereupon the admission of refrigerant to the cooling pipes will cause a contraction of the control fluid and a closing of the expansion valve. l

As an important feature of my invention I provide for the mounting of the thermo-control tube in the refrigerating room for thermo engagement with the air of the room as contrasted with the thermo engagement with the refrigerant as has, to my knowledge, been the practice heretofore. By reason of this arrangement not only are the inconsistencies of control caused by irregular temperatures of adjacent moving pockets of refrigerant entirely eliminated, but advantage is taken of the heat mixing and distributing properties of the air to apply a mean temperature to the control tube and to avoid the extreme temperature differences of certain of the adjacent refrigerant pockets aforesaid. I

An additional automatic control ofthe valve parts is'provided which serves to modulate'the opening and closing of the valve by thermo-control tube in accordance with the back pressure in the cooling pipes. This is here effected by 60 theextension across the chamber I3 below the inlet and discharge nipples of a flexible diaphragm 42 which defines an individual chamber 43 arranged to expand or contract in accordance with the pressure in the cooling pipes and against the atmosphere admitted to the central open portion of the casing chamber. Preferably the upper section 39 of the stem 31 is extended through the diaphragm 42 and the latter clamped. to the valve yoke by means of nuts 44 threadably carried on the stem 'setttion whereby 'the yoke will be moved to valve closing and valve opening position respectively onfxpansion or contragtion of the. chamber 43. Thus with an increase in temperature in the refrigerator and a corresponding decrease in pressure in cooling valve, 35-

pipes, the chamber 43 will tend to contract to open the valve against the action of the spring 2| and augmented by the pressure in, the thermocontrol chamber 36. On the other hand a decrease in temperature in the cooling pipes will be'followed by an expansion of the chamber 43 and a consequent closing of the valve. Since the action of the thermocontrol tube and the back pressure in the cooling pipes, each impart a regulation to the valve calculated to accomplish the same result,it will be understood that the actual regulation will be a mean of the two separate and approximate regulations thereby approaching a more even regulation than would result from either of the separate regulations taken alone.

This modulated dual regulationis of additional usefulness in that it makes possible the continued use of the valve in the event of breakage of the thermo-control tube and pending repair or replacement of the tube. In this latter case the entire control of the valve is shifted to the back pressure chamber 43. Preferably,.

when the valve is so. used, the plate 22 is retracted to relieve the tension on the spring 2| suflicient to offset the loss of force normally afiorded by the pressure chamber 36.

In order to protect the diaphragm 42 against possibility of overstrain due to the presence at' any time of too great a pressure in the chamber '43, a one way check valve 46 is preferably inserted in the line at the discharge side of the expansion valve for preventing the transfer of refrigerant from the cooling pipes back to the expansion valve.

As'an important feature of my invention, I

provide for the maintaining of the expansion valve and parts thereof relatively warm and thereby protected against freezing or sticking. This is here accomplished by the provision in the walls of the casing of a fluid jacket 41 which is communicated as by a port 48 with the inlet nipple l4,- for filling thereof with liquid refrigerant. Since, as will be understood, the liquid refrigerant as received from the compresser is warm-relative to the expanded refrigerant, the presence of the liquid about the valve will main tain the parts thereof against freezing,

As an additional feature of my invention I provide for the individual control of a plurality of refrigerating units which are fed from a,

common compressor. "In the carrying out of this arrangement I use a theremostatically controlled valve 49 of similar design to the expansion valve above described and which is inserted in the refrigerant line between the dis- ,charge end of the cooling pipe and the compressor and is arranged to close upon the lowering of the temperature of the associated unit to a predetermined amount. In this way the unit is automatically shut ofi and isolated from The construction of the ermostatic valve 49, as shown in Figure 2, is e ntially the same as that of the expansion valve and is arranged by fiason of its similar control by the tempera? ture of the air in the refrigerating room' to open andclose substantially simultaneously with the expansion valve. In view of the fact that the valve 49 is substantially solely in contact with the expanded refrigerant and need not present an appreciable pressure. drop therethrough when open for vaporization, the valve port l1 and valve l8 therefor are preferably arranged to provide a considerably larger valve opening than the corresponding opening in the expansion valve. Also it has been found-that due to the positioning of this valve at a warmer point in the refrigerant circuit the warming jacket preferably used in the case'ofthe exrpension valve may be dispensed with.-

I claim:

walled casing defining between the walls thereof a Jacket and providing at the interior thereof a valveehamberan inlet and discharge means erant line, said inlet means comprising a con-- duit extending through said casing and into said chamber and vented at a portion thereof opposite the walls of said casing to said jacket,

and a valve in said chamber movable to and.

from said conduit to regulate the refrigerant flow into said chamber.

2. A refrigerant control comprising a valve casing having a valve chamber and provided with inlet and discharge nipples for connection .in a refrigerant line and communicating with said chamber, said inlet nipple being extended into said chamber and having an outlet opening at a side thereof, a yoke member surrounding said inlet nipple, a plug valve adiustably carried by said yoke formovement to and from a closed position in said opening, a spring forurging said yoke member to valve closing position, means extending without the casing for.

adjusting the tension of said spring, means extending without said casing for moving the valve plug relative-to said yoke member for adjusting the relative amount of valve opening, a diaphragm across said chamber and connected to said yoke member and defining an individual 50 expandible chamber including the inlet and 'dis- 1 charge nipples and said valve and arranged to open said valve against the urge of 'said spring in. accordance with theback pressure at said discharge nipple, a second diaphragm extending 'across said first chamber to define with said casing a second expandible chamber, a thermo-control tube connected to said casing in communication with said chamber whereby expansion or contraction of said second diaphragm will be effected in accordance with the temperature of said tube, and a stem connecting said second diaphragm and yoke member for opentng'or closing of said valve in accordance with the temperature of said tube, said stem comprising removable sections one of which being adiustably secured to said yoke member.

3. A refrigerant control comprising a. casingdefining a chamber and provided'with inlet and discharge nipples for connection in a refrig-' erant line and communicating with said chamber, a valve movable to and from a closed position imengagement with said inlet nipple, a spring for urging said valve-to closed position, means extending without the casing for adjust- .26 1. A refrigerant controlcomprising a double,

'for communicating said chamber with a refriging the tension of said spring. a diaphragm across said chamber and connected to said valve and defining an individual expandible chamber including the-inlet and discharge nipples and said valve and arranged to open said valve against the urge of said spring in accordance with the back pressure at said discharge nipple, a second diaphragm extending across said first chamber to define with said casing a second ex- Pandible chamber, athermo-control tube connected to said casing in communication with saidchamber whereby expansion or contraction of said second diaphragm willbe etiected in ac-L cordance withthe temperature-of said tube -and' means connecting said diaphragm and valve for opening or closing oi the latter in accordance with the temperature of said tube.

THOMAS DRUMMOND. 

